Your hair is not too bad, your male pattern baldness pattern looks very similar to mine at the moment (your hair is a bit better than mine). Im around a NW2 w/ diffuse thinning..
However, your only 17 and I dont want to sound negative or anything but most of the time when you start losing it that young it tends to be aggressive male pattern baldness.
If I were you I would keep close watch of my hair by taking pics every couple of months and if it continues to thin or recede then I would look at my options (either shave it and forget about it, or fight it by getting on Propecia, or Nizoral, or Rogaine, or a combination of the 3).
Although I would kind of be cautious of getting on anything that messes with hormones at your age such as Propecia or Dutasteride because your still very young.
I have been using Propecia, Minoxidil, and Nizoral for about 2 1/2 - 3 years now. I got on it when I was 22 and although I continue to thin slowly but surely, my hairline hasn't receeded too much. I think it has helped in maintenance but who knows, it might have been same if I never used any meds at all or it could have been a lifesaver. Do alot of research, think it through, and make an informed decision if you choose to use the meds. Good luck!